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1da177e4 LT |
1 | /* |
2 | * Description: EBTables 802.1Q match extension kernelspace module. | |
3 | * Authors: Nick Fedchik <nick@fedchik.org.ua> | |
4 | * Bart De Schuymer <bdschuym@pandora.be> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
e664eabd | 17 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
1da177e4 LT |
18 | */ |
19 | ||
20 | #include <linux/if_ether.h> | |
21 | #include <linux/if_vlan.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/moduleparam.h> | |
18219d3f | 24 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
25 | #include <linux/netfilter_bridge/ebtables.h> |
26 | #include <linux/netfilter_bridge/ebt_vlan.h> | |
27 | ||
1da177e4 LT |
28 | #define MODULE_VERS "0.6" |
29 | ||
1da177e4 | 30 | MODULE_AUTHOR("Nick Fedchik <nick@fedchik.org.ua>"); |
f776c4cd | 31 | MODULE_DESCRIPTION("Ebtables: 802.1Q VLAN tag match"); |
1da177e4 LT |
32 | MODULE_LICENSE("GPL"); |
33 | ||
1da177e4 | 34 | #define GET_BITMASK(_BIT_MASK_) info->bitmask & _BIT_MASK_ |
8cc784ee | 35 | #define EXIT_ON_MISMATCH(_MATCH_,_MASK_) {if (!((info->_MATCH_ == _MATCH_)^!!(info->invflags & _MASK_))) return false; } |
1da177e4 | 36 | |
8cc784ee | 37 | static bool |
62fc8051 | 38 | ebt_vlan_mt(const struct sk_buff *skb, struct xt_action_param *par) |
1da177e4 | 39 | { |
f7108a20 | 40 | const struct ebt_vlan_info *info = par->matchinfo; |
1da177e4 LT |
41 | |
42 | unsigned short TCI; /* Whole TCI, given from parsed frame */ | |
43 | unsigned short id; /* VLAN ID, given from frame TCI */ | |
44 | unsigned char prio; /* user_priority, given from frame TCI */ | |
45 | /* VLAN encapsulated Type/Length field, given from orig frame */ | |
47c183fa | 46 | __be16 encap; |
1da177e4 | 47 | |
df8a39de JP |
48 | if (skb_vlan_tag_present(skb)) { |
49 | TCI = skb_vlan_tag_get(skb); | |
13937911 JG |
50 | encap = skb->protocol; |
51 | } else { | |
52 | const struct vlan_hdr *fp; | |
53 | struct vlan_hdr _frame; | |
54 | ||
55 | fp = skb_header_pointer(skb, 0, sizeof(_frame), &_frame); | |
56 | if (fp == NULL) | |
57 | return false; | |
58 | ||
59 | TCI = ntohs(fp->h_vlan_TCI); | |
60 | encap = fp->h_vlan_encapsulated_proto; | |
61 | } | |
1da177e4 LT |
62 | |
63 | /* Tag Control Information (TCI) consists of the following elements: | |
64 | * - User_priority. The user_priority field is three bits in length, | |
65 | * interpreted as a binary number. | |
66 | * - Canonical Format Indicator (CFI). The Canonical Format Indicator | |
67 | * (CFI) is a single bit flag value. Currently ignored. | |
68 | * - VLAN Identifier (VID). The VID is encoded as | |
7f495ad9 IM |
69 | * an unsigned binary number. |
70 | */ | |
1da177e4 LT |
71 | id = TCI & VLAN_VID_MASK; |
72 | prio = (TCI >> 13) & 0x7; | |
1da177e4 LT |
73 | |
74 | /* Checking VLAN Identifier (VID) */ | |
75 | if (GET_BITMASK(EBT_VLAN_ID)) | |
76 | EXIT_ON_MISMATCH(id, EBT_VLAN_ID); | |
77 | ||
78 | /* Checking user_priority */ | |
79 | if (GET_BITMASK(EBT_VLAN_PRIO)) | |
80 | EXIT_ON_MISMATCH(prio, EBT_VLAN_PRIO); | |
81 | ||
82 | /* Checking Encapsulated Proto (Length/Type) field */ | |
83 | if (GET_BITMASK(EBT_VLAN_ENCAP)) | |
84 | EXIT_ON_MISMATCH(encap, EBT_VLAN_ENCAP); | |
85 | ||
8cc784ee | 86 | return true; |
1da177e4 LT |
87 | } |
88 | ||
b0f38452 | 89 | static int ebt_vlan_mt_check(const struct xt_mtchk_param *par) |
1da177e4 | 90 | { |
9b4fce7a JE |
91 | struct ebt_vlan_info *info = par->matchinfo; |
92 | const struct ebt_entry *e = par->entryinfo; | |
1da177e4 | 93 | |
1da177e4 LT |
94 | /* Is it 802.1Q frame checked? */ |
95 | if (e->ethproto != htons(ETH_P_8021Q)) { | |
ff67e4e4 JE |
96 | pr_debug("passed entry proto %2.4X is not 802.1Q (8100)\n", |
97 | ntohs(e->ethproto)); | |
bd414ee6 | 98 | return -EINVAL; |
1da177e4 LT |
99 | } |
100 | ||
101 | /* Check for bitmask range | |
7f495ad9 IM |
102 | * True if even one bit is out of mask |
103 | */ | |
1da177e4 | 104 | if (info->bitmask & ~EBT_VLAN_MASK) { |
ff67e4e4 JE |
105 | pr_debug("bitmask %2X is out of mask (%2X)\n", |
106 | info->bitmask, EBT_VLAN_MASK); | |
bd414ee6 | 107 | return -EINVAL; |
1da177e4 LT |
108 | } |
109 | ||
110 | /* Check for inversion flags range */ | |
111 | if (info->invflags & ~EBT_VLAN_MASK) { | |
ff67e4e4 JE |
112 | pr_debug("inversion flags %2X is out of mask (%2X)\n", |
113 | info->invflags, EBT_VLAN_MASK); | |
bd414ee6 | 114 | return -EINVAL; |
1da177e4 LT |
115 | } |
116 | ||
117 | /* Reserved VLAN ID (VID) values | |
118 | * ----------------------------- | |
9d6f229f | 119 | * 0 - The null VLAN ID. |
1da177e4 | 120 | * 1 - The default Port VID (PVID) |
9d6f229f | 121 | * 0x0FFF - Reserved for implementation use. |
7f495ad9 IM |
122 | * if_vlan.h: VLAN_N_VID 4096. |
123 | */ | |
1da177e4 LT |
124 | if (GET_BITMASK(EBT_VLAN_ID)) { |
125 | if (!!info->id) { /* if id!=0 => check vid range */ | |
b738127d | 126 | if (info->id > VLAN_N_VID) { |
ff67e4e4 JE |
127 | pr_debug("id %d is out of range (1-4096)\n", |
128 | info->id); | |
bd414ee6 | 129 | return -EINVAL; |
1da177e4 LT |
130 | } |
131 | /* Note: This is valid VLAN-tagged frame point. | |
9d6f229f | 132 | * Any value of user_priority are acceptable, |
1da177e4 | 133 | * but should be ignored according to 802.1Q Std. |
7f495ad9 IM |
134 | * So we just drop the prio flag. |
135 | */ | |
1da177e4 LT |
136 | info->bitmask &= ~EBT_VLAN_PRIO; |
137 | } | |
138 | /* Else, id=0 (null VLAN ID) => user_priority range (any?) */ | |
139 | } | |
140 | ||
141 | if (GET_BITMASK(EBT_VLAN_PRIO)) { | |
142 | if ((unsigned char) info->prio > 7) { | |
ff67e4e4 JE |
143 | pr_debug("prio %d is out of range (0-7)\n", |
144 | info->prio); | |
bd414ee6 | 145 | return -EINVAL; |
1da177e4 LT |
146 | } |
147 | } | |
148 | /* Check for encapsulated proto range - it is possible to be | |
149 | * any value for u_short range. | |
7f495ad9 IM |
150 | * if_ether.h: ETH_ZLEN 60 - Min. octets in frame sans FCS |
151 | */ | |
1da177e4 LT |
152 | if (GET_BITMASK(EBT_VLAN_ENCAP)) { |
153 | if ((unsigned short) ntohs(info->encap) < ETH_ZLEN) { | |
ff67e4e4 JE |
154 | pr_debug("encap frame length %d is less than " |
155 | "minimal\n", ntohs(info->encap)); | |
bd414ee6 | 156 | return -EINVAL; |
1da177e4 LT |
157 | } |
158 | } | |
159 | ||
bd414ee6 | 160 | return 0; |
1da177e4 LT |
161 | } |
162 | ||
043ef46c JE |
163 | static struct xt_match ebt_vlan_mt_reg __read_mostly = { |
164 | .name = "vlan", | |
001a18d3 JE |
165 | .revision = 0, |
166 | .family = NFPROTO_BRIDGE, | |
2d06d4a5 JE |
167 | .match = ebt_vlan_mt, |
168 | .checkentry = ebt_vlan_mt_check, | |
fc0e3df4 | 169 | .matchsize = sizeof(struct ebt_vlan_info), |
1da177e4 LT |
170 | .me = THIS_MODULE, |
171 | }; | |
172 | ||
65b4b4e8 | 173 | static int __init ebt_vlan_init(void) |
1da177e4 | 174 | { |
ff67e4e4 | 175 | pr_debug("ebtables 802.1Q extension module v" MODULE_VERS "\n"); |
043ef46c | 176 | return xt_register_match(&ebt_vlan_mt_reg); |
1da177e4 LT |
177 | } |
178 | ||
65b4b4e8 | 179 | static void __exit ebt_vlan_fini(void) |
1da177e4 | 180 | { |
043ef46c | 181 | xt_unregister_match(&ebt_vlan_mt_reg); |
1da177e4 LT |
182 | } |
183 | ||
65b4b4e8 AM |
184 | module_init(ebt_vlan_init); |
185 | module_exit(ebt_vlan_fini); |